Container gardens comprising containers filled with plants are popular with individuals and businesses. In conventional systems, an empty container is filled with a growing medium, e.g., potting soil, and various plants then are planted in the growing medium. When using large containers, however, several problems typically arise. A large container completely filled with growing medium is very heavy, making it difficult to move the container. Also, the growing medium may block a drain hole in the container, occluding drainage of excess water. Further, roots may penetrate throughout the depth of the growing medium, making it difficult to remove the plants at the end of a growing season. If the container has a top opening that is narrower than the body of the container, it is very difficult to remove a plant if the roots have become entangled in the growing medium, forming a large mass of roots and growing medium. Thus, a need exists for an improved system and method for potting plants in containers.